1. Field of the Invention
The present invention relates to a hybrid battery module with a voltage balancing unit and its charging and discharging method; and more particularly to a hybrid battery module can be discharged by a voltage balancing unit so as to reach the goal of voltage balance, and no matter the hybrid battery module is in a charging mode or a discharging mode, once a cell set meets an abnormal or a critical safety event, the charging switch, the discharging switch and fuse of the two cell sets will simultaneously be turned off, so as to prevent the cell sets from being damaged.
2. Description of the Related Art
Regarding the conventional battery module and its charging and discharging method, such as a battery module with a plurality of cell sets disclosed in US patent Publication No. 20050116688 (US published patent application). The battery module is mainly used to prevent a single (or specific) cell from being decayed, and each cell set therein comprises one or more cells. Such hybrid battery module with voltage balancing unit uses the central processing unit (CPU) inside the electronic apparatus to determine which cell should be in the active state based on the number of the charging/discharging cycles of the cell. Therefore, each cell set is charged/discharged in a sequenced manner. However, once one of the cells encounters a problem during the charging/discharging operation, the forgoing patent is not able to turn off the battery charging switches simultaneously, which easily damages the battery module. Additionally, the cell sets of the forgoing patent are charged and discharged in series, thus its disadvantages are lower load capacity and longer charging/discharging time.